Increased Osteoblast Proliferation on Hydroxyapatite Thin Coatings Produced by Right Angle Magnetron Sputtering

Abstract:

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Crystalline hydroxyapatite thin coatings have been prepared using a novel opposing RF
magnetron sputtering approach at room temperature. X-ray diffraction (XRD) analysis shows that
all the principal peaks are attributable to HA, and the as-deposited HA coatings are made up of
crystallites in the size range of 50-100nm. Fourier transform infrared spectroscopy (FTIR) studies
reveal the existence of phosphate, carbonate and hydroxyl groups, suggesting that HA coatings are
highly crystalline. To study the biocompatibility of these coatings, murine osteoblast cells were
seeded onto various substrates. Cell density counts using fluorescence microscopy show that the
best osteoblast proliferation is achieved on an HA RAMS-coated titanium substrate. These
experiments demonstrate that RAMS is a promising coating technique for biomedical applications.

Abstract: Hydroxyapatite (HA) coatings were deposited on titanium substrate by means of pulsed laser
deposition (PLD) with Nd:YAG laser. Deposition was carried out at 20 Pa of water vapor atmosphere and
at room temperature. An Nd:YAG laser operating at a repetition rate of 10 HZ was used for deposition. In
above deposition condition, the HA coatings deposited by PLD at room temperature are amorphous phase,
and Ca/P ratio in HA coatings decreases with increasing water vapor pressure. The amorphous HA
coatings were recrystallized after hydrothermal treatment at 190°C for 10 h. The bonding strength of the
HA coating to the Ti substrate is up to 19.6 MPa. The structure and morphology of samples were
characterized by X-ray diffraction, Fourier transform infrared reflection specterophotometry, scanning
electron microcopy. The atomic ration of Ca and P was semiquantitatively determined by electron probe
micro analyzer.

Abstract: Calcium phosphate coatings were deposited on H2O2-treated carbon/carbon composites by ultrasonicated induction heating (UIH) method under different preparation conditions. The phase, morphology and composition of the calcium phosphate coatings were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM) and the adhesion strength of these coatings and the scratched morphologies were determined by the scratch test and stereomicroscope (STM). The results show that when the solution concentration is 0.003 M and pH value is 6, the phase of as-prepared coating is OCP, and When the solution concentration is larger than 0.0125 M and pH value is less than 5.5, all the as-prepared coatings are monetite with different morphologies. Among these calcium phosphate coatings, the moneite coating on H2O2-treated C/C prepared in 0.1M solution at 373K has the highest bonding strength whose critical load is on average 38 N.

Abstract: Nanocomposite Cr-W-B-N coatings with various tungsten contents were synthesized on silicon wafer substrates. The used technique is a DC reactive magnetron co-sputtering deposition equipped with a Cr-B alloy target with 20 at.% B and a W target in a mixed argon/nitrogen plasma atmosphere. Composition and microstructure of the obtained coatings were investigated using X-ray diffraction, X-ray Photoelectron Spectroscope and transmission electron microscope while the micro-hardness was measured using a depth-sensing nano-indenter. The results have shown that the microstructure and the mechanical properties of Cr-W-B-N coatings were strongly dependent on either the tungsten content or the volume fraction of W-N crystalline phases. It was observed that the micro-hardness of Cr-W-B-N coatings is lower than that of Cr-B-N coating as the tungsten content is less than 24 at.% and the volume fraction of W-N crystalline phases is lower than 37 vol.%. As the tungsten content further increased to 30 at.% and the volume fraction of W-N crystalline phases increased to 55 vol.%, the micro-hardness of Cr-W-B-N coating was found enhanced to 19 GPa and higher than Cr-B-N film. It was also obtained that the volume fraction of Cr-N crystalline phases is inversely proportional to the volume fraction of W-N crystalline phases.